Method for manufacturing laminated iron core and apparatus for manufacturing laminated iron core

ABSTRACT

A method for manufacturing a laminated iron core includes setting a blanking position on a strip-shaped workpiece for iron core pieces each including a yoke piece part having a linear shape and a magnetic pole piece part extending from the yoke piece part, such that a pair of iron core pieces are opposed each other and the magnetic pole piece part of one iron core piece is arranged between adjacent magnetic pole piece parts of the other iron core piece among the pair of iron core pieces, simultaneously blanking a front end side of the magnetic pole piece part and a back surface side of the yoke piece part of the one iron core piece from the strip-shaped workpiece before simultaneously blanking those of the other iron core piece from the strip-shaped workpiece, and blanking the iron core pieces from the strip-shaped workpiece.

CROSS REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority ofJapanese Patent Application No. 2016-057136 filed on Mar. 22, 2016, thecontents of which are incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a method for manufacturing a laminatediron core formed by blanking iron core pieces from a strip-shapedworkpiece and laminating the iron core pieces, and an apparatus formanufacturing the laminated iron core.

2. Description of the Related Art

A method for manufacturing a laminated iron core includes, for example,the following methods (A) to (C).

Method (A): The method for laminating linear strip-shaped iron corepieces (by one wind) blanked and formed from a strip-shaped workpiece bya die unit and forming a strip-shaped laminated iron core and annularlyfolding this strip-shaped laminated iron core and forming a laminatediron core (see Japanese Patent No. 3782533 as Patent Literature 1).

Method (B): The method for laminating while annularly winding linearstrip-shaped iron core pieces blanked and formed from a strip-shapedworkpiece by a die unit and forming a laminated iron core (seeJP-B-7-101976 as Patent Literature 2).

Method (C): The method for annularly arranging a plurality of dividedlaminated iron cores in which divided iron core pieces (divided corepieces) blanked and formed from a strip-shaped workpiece by a die unitare laminated to form a laminated iron core.

In those cases, yield (material yield) of the strip-shaped workpiece canbe improved by blanking the strip-shaped iron core pieces of two rows inthe methods (A) and (B) and iron core piece groups (hereinafter simplycalled the iron core piece groups) of two rows formed by linearlyarranging divided yoke piece parts of the plurality of divided iron corepieces in the method (C) from the strip-shaped workpiece in a layouthaving a state in which a magnetic pole piece part of the other row isarranged and opposed between adjacent magnetic pole piece parts (slot)of one row, that is, the magnetic pole piece parts of the rows aremated.

At this time, in order to maximize the yield of the strip-shapedworkpiece, it is necessary to previously blank a front end (for example,the inside diameter side) of the magnetic pole piece part, for example,under the influence of dimension accuracy or the restrictions ofarrangement of the die unit in the case of attempting to bring positionsof the opposed strip-shaped iron core pieces or the opposed iron corepiece groups of the two rows nearer.

As a method for previously blanking the front end of this magnetic polepiece part, for example, Patent Literature 2 or JP-A-2003-164080 asPatent Literature 3 mentions that the front ends of the magnetic polepiece parts of the strip-shaped iron core pieces or the iron core piecegroups of the two rows are simultaneously blanked in consideration of,for example, a balance of blanking or a decrease in a blanking step.

Also, Patent Literature 2 mentions that back surfaces (for example, theoutside diameter side) of yoke piece parts of two rows aresimultaneously blanked in a different step.

In addition, in the method (A), a strip-shaped iron core piece can beobtained from a strip-shaped workpiece by blanking all the back surfaceof a yoke piece part in a blanking step as described in PatentLiterature 3. Particularly, for example, when blanking requires a highload for a long strip-shaped iron core piece, before the blanking step,a part of the back surface of the yoke piece part is slit and in theblanking step, a gap between the slits of the back surfaces is blankedand thereby, a press load in one step can be decreased. Also in thiscase, the method for simultaneously blanking the front ends of themagnetic pole piece parts of the strip-shaped iron core pieces in thesame step and simultaneously blanking the slits of the back surfaces ofthe yoke piece parts in a different step is adopted.

Patent Literature 1: Japanese Patent No. 3782533

Patent Literature 2: JP-B-7-101976

Patent Literature 3: JP-A-2003-164080

SUMMARY OF THE INVENTION

A dimension S ranging from a front end of a magnetic pole piece part 92to a back surface of a yoke piece part 93 becomes important in blankingof strip-shaped iron core pieces 90, 91 (similarly, iron core piecegroups) of two rows shown in FIG. 4. That is, a distance S from ablanked part 94 to a blanked part 95. As a result, the method forsimultaneously blanking the front ends of the magnetic pole piece parts92 of the strip-shaped iron core pieces 90, 91 of the two rows andsimultaneously blanking the back surfaces of the yoke piece parts 93 ina different step has a problem that the dimension S does not becomestable under the influence of, for example, expansion of the material.FIG. 4 shows the blanked part 94 of the front end side of the magneticpole piece part 92, and the blanked part 95 of the back surface side ofthe yoke piece part 93.

This problem can be partly solved by adjusting a position of the dieunit, but the dimensions S cannot be adjusted individually, with theresult that even when the dimension of one row has no problem, itbecomes necessary to adjust the dimension of the other row andconsequently, it becomes difficult to perform high-accuracy blanking.

The present invention has been implemented in view of suchcircumstances, and a non-limited object of the present invention is toprovide a method for manufacturing a laminated iron core capable ofblanking an iron core piece from a strip-shaped workpiece with goodworkability and high accuracy.

An aspect of the present invention is to provide a method formanufacturing a laminated iron core, including: setting a blankingposition on a strip-shaped workpiece for iron core pieces each includinga yoke piece part having a linear shape and a magnetic pole piece partextending from the yoke piece part, such that a pair of iron core piecesare opposed each other and the magnetic pole piece part of one iron corepiece is arranged between adjacent magnetic pole piece parts of theother iron core piece among the pair of iron core pieces; simultaneouslyblanking a front end side of the magnetic pole piece part and a backsurface side of the yoke piece part of the one iron core piece from thestrip-shaped workpiece before simultaneously blanking a front end sideof the magnetic pole piece part and a back surface side of the yokepiece part of the other iron core piece from the strip-shaped workpiece;and blanking the iron core pieces from the strip-shaped workpiece.

The method for manufacturing the laminated iron core may furtherincluding laminating the iron core pieces to form the laminated ironcore.

The method may be configured such that each of the iron core pieces is alinear strip-shaped iron core piece having the linear yoke piece part,and the laminated iron core is formed by laminating the linearstrip-shaped iron core pieces and then annularly bending the linearstrip-shaped iron core pieces.

The method may be configured such that each of the iron core pieces is alinear strip-shaped iron core piece having the linear yoke piece part,and the laminated iron core is formed by laminating while annularlywinding the linear strip-shaped iron core pieces.

The method may be configured such that each of the iron core piecesincludes a plurality of divided iron core pieces, and the laminated ironcore is formed by annularly arranging a divided laminated iron core inwhich the plurality of divided iron core pieces are laminated.

The method may be configured such that the back surface side of the yokepiece part of each of the iron core pieces is blanked at a distance in alongitudinal direction of the yoke piece part to remain a non-blankedportion, and the non-blanked portion of the back surface side of theyoke piece part is blanked when separating each of the iron core piecesfrom the strip-shaped workpiece.

The method may be configured such that the pair of iron core pieces aresequentially blanked in a state where a longitudinal direction of eachof the iron core pieces is aligned with a direction orthogonal to aconveyance direction of the strip-shaped workpiece.

The method may be configured such that the pair of iron core pieces aresequentially blanked in a state where a longitudinal direction of eachof the iron core pieces is aligned with a direction different from adirection orthogonal to a conveyance direction of the strip-shapedworkpiece.

The method for manufacturing the laminated iron core may furtherincluding blanking a portion between adjacent lateral parts of themagnetic pole piece part of the one iron core piece and the magneticpole piece part of the other iron core piece before blanking the frontend side of the magnetic pole piece part and the back surface side ofthe yoke piece part of each of the iron core pieces.

Another aspect of the present invention provides an apparatus formanufacturing a laminated iron core, which sets a blanking position on astrip-shaped workpiece for iron core pieces each including a yoke piecepart having a linear shape and a magnetic pole piece part extending fromthe yoke piece part, such that a pair of iron core pieces are opposedeach other and the magnetic pole piece part of one iron core piece isarranged between adjacent magnetic pole piece parts of the other ironcore piece among the pair of iron core pieces, and blanks the iron corepieces from the strip-shaped workpiece, the apparatus including: a firstdie unit including a first die and a first punch which simultaneouslyblank a front end side of the magnetic pole piece part and a backsurface side of the yoke piece part of the one iron core piece from thestrip-shaped workpiece; and a second die unit including a second die anda second punch which simultaneously blank a front end side of themagnetic pole piece part and a back surface side of the yoke piece partof the other iron core piece, the second die unit being arranged in adownstream side from the first die unit.

The apparatus may be configured such that each of the first die and thefirst punch and each of the second die and the second punch blank theback surface side of the yoke piece part of each of the iron core piecesat a distance in a longitudinal direction of the yoke piece part toremain an non-blanked portion, and the apparatus further includes athird die unit including a third die and a third punch which blank thenon-blanked portion left in the back surface side of the yoke piece partof each of the iron core pieces and separate each of the iron corepieces from the strip-shaped workpiece, the third die unit beingarranged in a downstream side from the first die unit and the second dieunit. For example, a part of the back surface side of the yoke piecepart of each of the plurality iron core pieces is blanked such that anon-blanked portion remains.

The apparatus may further include a fourth die unit including a fourthdie and a fourth punch which blank a portion between adjacent lateralparts of the magnetic pole piece part of the one iron core piece and themagnetic pole piece part of the other iron core piece, the fourth dieunit being arranged in an upstream side from the first die unit and thesecond die unit.

The method and the apparatus for manufacturing the laminated iron coreaccording to the aspects of the present invention simultaneously blankthe front end side of the magnetic pole piece part and the back surfaceside of the yoke piece part of each of the iron core pieces in the caseof blanking the pair of iron core pieces from the strip-shapedworkpiece, with the result that accuracy of a dimension ranging from afront end of the magnetic pole piece part to a back surface of the yokepiece part can be improved. Also, in the case of blanking the iron corepieces, a position adjustment of the die unit can be made with respectto each of the iron core pieces, with the result that the positionadjustment of the die unit is facilitated, and time consuming for theposition adjustment can also be shortened.

Consequently, the iron core piece can be blanked from the strip-shapedworkpiece with good workability and high accuracy.

Also, when the back surface side of the yoke piece part of each of theiron core pieces is blanked at the distance in the longitudinaldirection of the yoke piece part, a press load in this blanking step canbe decreased.

And, in the case of blanking the portion between the opposed lateralparts of the mated magnetic pole piece parts, this blanking causesexpansion in the strip-shaped workpiece. As a result, by simultaneouslyblanking the front end side of the magnetic pole piece part and the backsurface side of the yoke piece part of each of the iron core piecesafter this blanking, the accuracy of the dimension ranging from thefront end of the magnetic pole piece part to the back surface of theyoke piece part can be improved, with the result that, for example, thenumber of position adjustments of the die unit can be decreased.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is an explanatory diagram of a method for manufacturing alaminated iron core according to one embodiment of the presentinvention;

FIG. 2 is an explanatory diagram of a method for manufacturing thelaminated iron core;

FIG. 3 is an explanatory diagram of a method for manufacturing alaminated iron core according to another embodiment of the presentinvention;

FIG. 4 is an explanatory diagram of a method for manufacturing alaminated iron core according to a related example; and

FIG. 5 is an schematic diagram of an apparatus for manufacturing alaminated iron core according to one embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Subsequently, an embodiment of the present invention will be describedwith reference to the accompanying drawings, and the present inventionwill be understood.

First, a laminated iron core manufactured by a method for manufacturingthe laminated iron core according to one embodiment of the presentinvention will be described with reference to FIGS. 1 and 2.

The laminated iron core is a stator iron core (or simply referred to asstator) used in an inner rotor type.

This laminated iron core is formed by laminating a plurality of sets ofa pair of (paired) iron core pieces 10, 11.

Each of the iron core pieces 10, 11 is blanked and formed from astrip-shaped workpiece (thin metal sheet) 12 made of, for example, anamorphous material or an electromagnetic steel plate with a thickness ofabout 0.10 to 1.2 mm. In FIGS. 1 and 2, the width (the length of each ofthe iron core pieces 10, 11 in a longitudinal direction) of thestrip-shaped workpiece 12 is narrowed and described for convenience ofdescription.

Concretely, each of the iron core pieces 10, 11 is a linear strip-shapediron core piece having a linear yoke piece part 13 and a plurality ofmagnetic pole piece parts 18 extending from this yoke piece part 13. Inthe case of manufacturing the laminated iron core, the laminated ironcore is formed by laminating a plurality of strip-shaped iron corepieces 10 and a plurality of strip-shaped iron core pieces 11 formed inlinear shapes and then respectively annularly folding laminated bodies(strip-shaped laminated iron cores) of the strip-shaped iron core pieces10 and the strip-shaped iron core pieces 11 and laminating the twolaminated bodies. In addition, when the length of the iron core piece(strip-shaped iron core piece) is short, the laminated iron core canalso be formed by respectively semi-circularly folding the laminatedbodies (strip-shaped laminated iron cores) of the two strip-shaped ironcore pieces and annularly arranging the laminated bodies.

Each of the iron core pieces 10, 11 is a piece blanked from onestrip-shaped workpiece, but may be a piece blanked from plural (forexample, two, or three or more) stacked strip-shaped workpieces.

Also, the radial width of the yoke piece part 13 is equal, but may bepartially narrowed.

The iron core pieces 10 adjacent in a lamination direction and the ironcore pieces 11 adjacent in the lamination direction are respectivelymutually joined by caulking parts (caulking holes 34, 38, caulkingprojections 35, 39 described below), but can also be joined using anyone or two or more of a resin (a thermosetting resin (for example, anepoxy resin) or a thermoplastic resin), an adhesive and welding.

In addition, the plurality of iron core pieces forming the laminatediron core can have the following configuration.

Each of the iron core pieces is a linear strip-shaped iron core piecehaving a linear yoke piece part and plural magnetic pole piece partsextending from this yoke piece part, and the length of the yoke piecepart is long, and in the case of manufacturing the laminated iron core,the laminated iron core is formed by annularly winding and alsolaminating each of the strip-shaped iron core pieces formed in linearshapes.

In this case, each of the iron core pieces is blanked from thestrip-shaped workpiece in a state where the longitudinal direction ofeach of the iron core pieces is aligned with a conveyance direction ofthe strip-shaped workpiece.

Also, each of iron core pieces 10 a, 11 a shown in FIG. 3 as anotherembodiment includes a plurality of divided iron core pieces 16, and hasdiscontinuous divided yoke piece parts 15 of the divided iron corepieces 16. In the case of manufacturing the laminated iron core, thelaminated iron core is formed by annularly arranging plural dividedlaminated iron cores constructed by laminating the divided iron corepieces 16 (.

In addition, in each of the divided iron core pieces 16, one magneticpole piece part 17 extends from one divided yoke piece part 15, but aplurality of magnetic pole piece parts may extend.

The laminated iron core formed by laminating the iron core pieces 10, 11has an annular yoke part and a plurality of magnetic pole partsconnected integrally to an inner peripheral side of this yoke part.

The yoke part and the magnetic pole parts are respectively formed of thelaminated yoke piece parts 13 and the laminated magnetic pole pieceparts 18 by laminating the plurality of iron core pieces 10, 11 havingthe yoke piece parts 13 and the plurality of magnetic pole piece parts18. In addition, the magnetic pole piece part 18 is formed by blanking aslot 19 from the strip-shaped workpiece.

FIG. 5 shows an apparatus 132 for manufacturing the laminated iron coreaccording to one embodiment of the present invention. For example, thestrip-shaped workpiece 12 is sequentially fed from a winding storagethrough a drawing apparatus 119, a correction apparatus 120 and afeeding apparatus 130 toward the apparatus 132 for manufacturing thelaminated iron core. In the apparatus 132 for manufacturing thelaminated iron core, the strip-shaped workpiece 12 is punched andblanked to produce the iron core pieces 10, 11 by using dies and punchesof die units 131.

Subsequently a method for manufacturing the laminated iron coreaccording to one embodiment of the present invention will be describedwith reference to FIGS. 1 and 2.

The method for manufacturing the laminated iron core is a method forforming the laminated iron core by conveying the strip-shaped workpiece12 with a thickness of about 0.10 to 1.2 mm at a predetermined pitchusing the apparatus 132 for manufacturing the laminated iron core andalso blanking a plurality of sets of paired iron core pieces 10, 11 andsequentially laminating the iron core pieces 10, 11. The method includessteps A to K. In addition, the die units 131 are respectively arrangedin each of the steps A to K, and the apparatus 132 for manufacturing thelaminated iron core includes those die units 131.

A blanking position on the strip-shaped workpiece 12 for the paired ironcore pieces 10, 11 is set such that the yoke piece part 13 of each ofthe iron core pieces 10, 11 has a linear shape and the paired iron corepieces 10, 11 are opposed (opposed and arranged) and the magnetic polepiece part 18 of the other iron core piece 10 is mated and arrangedbetween the adjacent magnetic pole piece parts 18 of one iron core piece11.

In addition, a pair of the iron core pieces 10, 11 is sequentiallyblanked from the strip-shaped workpiece 12 in a state where thelongitudinal direction of each of the iron core pieces 10, 11 is alignedwith a direction (a width direction of the strip-shaped workpiece 12)orthogonal to the conveyance direction of the strip-shaped workpiece 12.

Hereinafter, detailed description will be made.

(Step A)

In the step A, pilot holes 20, 21 are blanked from the strip-shapedworkpiece 12.

Accordingly, the pilot holes 20 are formed in both sides of thestrip-shaped workpiece 12 in the width direction and the pilot holes 21are formed in the center of the strip-shaped workpiece 12 in the widthdirection at predetermined pitches, respectively. In addition, it isunnecessary to form the pilot hole 21, or the plurality of pilot holes21 can also be spaced in the width direction of the strip-shapedworkpiece 12 according to the width of the strip-shaped workpiece 12.

(Step B)

In the step B, narrow slits 22, 23 having a longitudinal direction sameas the conveyance direction of the strip-shaped workpiece 12 are formedin both sides (insides from the pilot holes 20) of the strip-shapedworkpiece 12 in the width direction.

Accordingly, both sides of the strip-shaped workpiece 12 in the widthdirection are formed with one ends of the iron core pieces 10, 11 in thelongitudinal direction.

(Step C)

In the step C, a region (a portion between the slits 22, 23, the sameapplies hereinafter) for forming the iron core pieces 10, 11 of thestrip-shaped workpiece 12 is formed with plural paired slits 24, 25 atpredetermined pitches in the width direction of the strip-shapedworkpiece 12. This pair of slits 24, 25 is formed by blanking a portionbetween adjacent lateral parts of the magnetic pole piece part 18 of oneiron core piece 11 and the magnetic pole piece part 18 of the other ironcore piece 10 by a fourth die unit (not shown). In addition, the fourthdie unit includes a fourth die and a fourth punch corresponding tocontour shapes of the slits 24, 25.

Accordingly, a side surface of the magnetic pole piece part 18 of eachof the iron core pieces 10, 11 is formed in the width direction of thestrip-shaped workpiece 12.

Also, narrow slits 26, 27 are formed between the slits 22, 24 andbetween the slits 23, 24, respectively.

Accordingly, both sides of the strip-shaped workpiece 12 in the widthdirection are formed with the other ends of the iron core pieces 10, 11in the longitudinal direction.

(Step D)

In the step D, the region for forming the iron core pieces 10, 11 of thestrip-shaped workpiece 12 is formed with a plurality of narrow slits 28and blanked parts 29 in the width direction of the strip-shapedworkpiece 12. The plurality of slits 28 and blanked parts 29 are formedby simultaneously blanking the front end side of the magnetic pole piecepart 18 and the back surface side of the yoke piece part 13 of the ironcore piece 11 by a first die unit (not shown). In addition, the firstdie unit includes a first die and a first punch corresponding to contourshapes of the slits 28 and the blanked parts 29.

Here, the back surface side of the yoke piece part 13 is blanked at adistance in a longitudinal direction of the yoke piece part 13. Inaddition, the slit 28 formed by this blanking has the length ranging toa plurality of (about nine herein) magnetic pole piece parts 18.

Accordingly, a back surface of the yoke piece part 13 of the iron corepiece 11 is partially formed.

Also, the front end side of the magnetic pole piece part 18 of the ironcore piece 11 is blanked at a predetermined pitch in the width directionof the strip-shaped workpiece 12 so as to join the ends of a pair of theslits 24, 25 in the upstream side of the conveyance direction.

Accordingly, a front end surface of the magnetic pole piece part 18 ofthe iron core piece 11 is formed and also, a slot 19 of the iron corepiece 10 is formed.

(Step E)

In the step E, the region for forming the iron core pieces 10, 11 of thestrip-shaped workpiece 12 is formed with a plurality of narrow slits 30and blanked parts 31 in the width direction of the strip-shapedworkpiece 12. The plurality of slits 30 and blanked parts 31 are formedby simultaneously blanking the front end side of the magnetic pole piecepart 18 and the back surface side of the yoke piece part 13 of the ironcore piece 10 by a second die unit (not shown) arranged in the sidedownstream from the first die unit. In addition, the second die unitincludes a second die and a second punch corresponding to contour shapesof the slits 30 and the blanked parts 31.

In addition, blanking of the back surface side of the yoke piece part 13of the iron core piece 10 and blanking of the front end side of themagnetic pole piece part 18 are similar to those of the step D describedabove.

Accordingly, a back surface of the yoke piece part 13 of the iron corepiece 10 is partially formed and also, a front end surface of themagnetic pole piece part 18 of the iron core piece 10 and a slot 19 ofthe iron core piece 11 are formed.

By arranging the fourth die unit in the upstream side from the first andsecond die units as described above, the portion between the adjacentlateral parts of the mated magnetic pole piece parts 18 of the iron corepieces 10, 11 can be blanked before the front end sides of the magneticpole piece parts 18 and the back surface sides of the yoke piece parts13 of the iron core pieces 10, 11 are blanked.

Accordingly, the influence of expansion of the strip-shaped workpiececaused by blanking the portion between the adjacent lateral parts of themagnetic pole piece parts 18 on accuracy of a dimension ranging from thefront end of the magnetic pole piece part 18 to the back surface of theyoke piece part 13 can be decreased.

(Step F)

In the step F, pilot holes 32, 33 are blanked from the strip-shapedworkpiece 12.

The pilot holes 32 are formed between the pilot holes 20 adjacent in theconveyance direction formed in both sides of the strip-shaped workpiece12 in the width direction in the step A described above.

Also, the pilot hole 33 is formed between (in the vicinity of the pilothole 21 formed in the step A described above herein) a pair of the ironcore pieces 10, 11 and a pair of the iron core pieces 10, 11 adjacent inthe conveyance direction of the strip-shaped workpiece 12.

Accordingly, the accuracy of the dimension in the case of blanking canbe made higher.

Simultaneously, the region for forming the iron core piece 11 of thestrip-shaped workpiece 12 is formed with a caulking hole 34 in the ironcore piece 11 used as the lowermost layer of a laminated body. Inaddition, the caulking hole 34 may be formed in a different step.

(Step G)

In the step G, the region for forming the iron core piece 11 of thestrip-shaped workpiece 12 is formed with caulking projections 35 in theiron core pieces 11 used as layers other than the lowermost layer of thelaminated body.

(Step H)

In the step H, non-blanked parts 36, 37 left in the back surface side ofthe yoke piece part 13 in the case of forming the slit 28 in the step Ddescribed above are blanked. The non-blanked parts 36, 37 can be blankedby a third die unit (not shown) which is arranged in the downstream sidefrom the first and second die units and includes a third die and a thirdpunch.

Accordingly, the iron core pieces 11 are separated from the strip-shapedworkpiece 12 and also, the plurality of iron core pieces 11 formed withthe caulking projections 35 can be sequentially caulked and laminated onthe iron core piece 11 formed with the caulking hole 34 (the step oflaminating the plurality of iron core pieces 11).

(Step I)

In the step I, the region for forming the iron core piece 10 of thestrip-shaped workpiece 12 is formed with a caulking hole 38 in the ironcore piece 10 used as the lowermost layer of a laminated body.

(Step J)

In the step J, the region for forming the iron core piece 10 of thestrip-shaped workpiece 12 is formed with caulking projections 39 in theiron core pieces 10 used as layers other than the lowermost layer of thelaminated body.

(Step K)

In this step, non-blanked parts 40, 41 left in the back surface side ofthe yoke piece part 13 in the case of forming the slit 30 in the step Edescribed above are blanked. The non-blanked parts 40, 41 can be blankedby a die unit (not shown) with a configuration substantially similar tothat of the third die unit used in the step H described above.

Accordingly, the iron core pieces 10 are separated from the strip-shapedworkpiece 12 and also, the plurality of iron core pieces 10 formed withthe caulking projections 39 can be sequentially caulked and laminated onthe iron core piece 10 formed with the caulking hole 38 (the step oflaminating the plurality of iron core pieces 10).

The laminated iron core can be manufactured by respectively annularlyfolding the laminated bodies (strip-shaped laminated iron cores) of thestrip-shaped iron core pieces 10 and the strip-shaped iron core pieces11 manufactured by the method described above and laminating the twolaminated bodies.

In addition, when each of the iron core pieces 10 a, 11 a includesplural divided iron core pieces 16 and has discontinuous divided yokepiece parts 15 of the divided iron core pieces 16 as shown in FIG. 3,the iron core pieces 10 a, 11 a are blanked from a strip-shapedworkpiece by a method substantially similar to the method describedabove, with the result that steps C′ to E′ corresponding to the steps Cto E described above will herein be described briefly. In addition, FIG.3 describes a state where the adjacent divided iron core pieces 16constructing each of the iron core pieces 10 a, 11 a are separated, butthe adjacent divided iron core pieces 16 may abut.

(Step C′)

In the step C′, a region for forming the iron core pieces 10 a, 11 a ofthe strip-shaped workpiece is formed with a plurality of paired slits42, 43 at predetermined pitches in a width direction of the strip-shapedworkpiece. This pair of slits 42, 43 is formed by blanking a portionbetween adjacent lateral parts of a magnetic pole piece part 17 of oneiron core piece 11 a and a magnetic pole piece part 17 of the other ironcore piece 10 a.

Accordingly, a side surface of the magnetic pole piece part 17 of eachof the iron core pieces 10 a, 11 a is formed in the width direction ofthe strip-shaped workpiece.

(Step D′)

In the step D′, the region for forming the iron core pieces 10 a, 11 aof the strip-shaped workpiece is formed with a plurality of narrow slits44 and blanked parts 45 in the width direction of the strip-shapedworkpiece. The plurality of slits 44 and blanked parts 45 are formed bysimultaneously blanking the front end sides of the magnetic pole pieceparts 17 and the back surface sides of the plurality of divided yokepiece parts 15 of the iron core piece 11 a.

Here, the back surface side of the divided yoke piece part 15 is blankedat a distance 46 a in a longitudinal direction of the divided yoke piecepart 15. In addition, the slit 44 formed by this blanking has the lengthranging to the adjacent magnetic pole piece parts 17.

Accordingly, a back surface of the divided yoke piece part 15 of theiron core piece 11 a is partially formed.

Also, the front end side of the magnetic pole piece part 17 is blankedat a predetermined pitch in the width direction of the strip-shapedworkpiece so as to join the ends of a pair of the slits 42, 43 in theupstream side of the conveyance direction.

Accordingly, a front end surface of the magnetic pole piece part 17 ofthe iron core piece 11 a is formed and also, a slot 19 a of the ironcore piece 10 a is formed.

(Step E′)

In the step E′, the region for forming the iron core pieces 10 a, 11 aof the strip-shaped workpiece is formed with a plurality of narrow slits47 and blanked parts 48 in the width direction of the strip-shapedworkpiece. The plurality of slits 47 and blanked parts 48 are formed bysimultaneously blanking the front end sides of the magnetic pole piecepart 17 and the back surface sides of the plurality of divided yokepiece parts 15 of the iron core piece 10 a.

In addition, blanking of the back surface side of the divided yoke piecepart 15 and blanking of the front end side of the magnetic pole piecepart 17 are similar to those of the step D′ described above.

Accordingly, a back surface of the divided yoke piece part 15 of theiron core piece 10 a is partially formed and also, a front end surfaceof the magnetic pole piece part 17 of the iron core piece 10 a and aslot 19 a of the iron core piece 11 a are formed.

In addition, a gap 46 between the adjacent divided yoke piece parts 15could be blanked before steps corresponding to the step H and the step Kof FIG. 2.

Also, when the gap 46 is absent, that is, the adjacent divided iron corepieces 16 abut, the adjacent divided yoke piece parts 15 are cut. Thiscutting method includes, for example, a method for depressing onedivided yoke piece part 15 against the other divided yoke piece part 15and cutting the divided yoke piece parts 15 and then pressing back andreturning to the same plane. In addition, this cutting is preferablymade in a step after (downstream from) the step E′.

As described above, the iron core piece can be blanked from thestrip-shaped workpiece with good workability and high accuracy by usingthe method and the apparatus for manufacturing the laminated iron coreaccording to the aspects of the present invention.

The present invention has been described above with reference to theembodiment, but the present invention is not limited to theconfiguration described in the embodiment described above, and alsoincludes other embodiments and modified examples contemplated within thescope of the matter described in the claims. For example, the case ofconstructing the method and the apparatus for manufacturing thelaminated iron core of the present invention by combining a part or allof the respective embodiments and modified examples described above isalso included in the scope of right of the present invention.

The embodiment described above describes the case of applying the methodand the apparatus for manufacturing the laminated iron core of thepresent invention to manufacture of the stator laminated iron core ofthe inner rotor type in which the rotor laminated iron core is arrangedinside the stator laminated iron core so as to have a gap, but themethod and the apparatus can also be applied to manufacture of a statorlaminated iron core of an outer rotor type in which a rotor laminatediron core is arranged outside the stator laminated iron core so as tohave a gap, and can also be applied to manufacture of a rotor laminatediron core.

In the embodiment described above, a pair of the iron core pieces isblanked from the strip-shaped workpiece in the state in which thelongitudinal direction of each of the iron core pieces is aligned withthe direction orthogonal to the conveyance direction of the strip-shapedworkpiece. However, the iron core pieces can also be blanked in a statein which the longitudinal direction of each of the iron core pieces isaligned with a direction different from the direction orthogonal to theconveyance direction of the strip-shaped workpiece, for example, theconveyance direction of the strip-shaped workpiece or an obliquedirection with respect to the conveyance direction (for example, seeJapanese Patent No. 4330420).

Also, the steps other than the steps D (D′) and the steps E (E′) can becombined freely, and can be divided into a plurality of steps.

Reference signs are listed as follows:

-   10, 10 a. 11, 11 a: IRON CORE PIECE-   12: STRIP-SHAPED WORKPIECE-   13: YOKE PIECE PART-   15: DIVIDED YOKE PIECE PART-   16: DIVIDED IRON CORE PIECE-   17, 18: MAGNETIC POLE PIECE PART-   19, 19 a: SLOT-   20, 21: PILOT HOLE-   22 to 28: SLIT-   29: BLANKED PART-   30: SLIT-   31: BLANKED PART-   32, 33: PILOT HOLE-   34: CAULKING HOLE-   35: CAULKING PROJECTION-   36, 37: NON-BLANKED PART-   38: CAULKING HOLE-   39: CAULKING PROJECTION-   40, 41: NON-BLANKED PART-   42 to 44: SLIT-   45: BLANKED PART-   46: GAP-   46 a: DISTANCE-   47: SLIT-   48: BLANKED PART-   119: DRAWING APPARATUS-   120: CORRECTION APPARATUS-   130: FEEDING APPARATUS-   131: DIE UNIT-   132: APPARATUS FOR MANUFACTURING LAMINATED IRON CORE

What is claimed is:
 1. A method for manufacturing a laminated iron core,comprising: setting a blanking position on a sheet of workpiece materialfor a plurality of iron core pieces, and each of the plurality of ironcore pieces including a yoke piece part having a linear shape andmagnetic pole piece parts extending from the yoke piece part, such thata pair of iron core pieces, among the plurality of iron core pieces, arelocated opposed to each other and respective ones of the magnetic polepiece parts of a first iron core piece, from the pair of iron corepieces, are arranged between respective adjacent ones of magnetic polepiece parts of a second iron core piece, from the pair of iron corepieces; simultaneously blanking a front end side of the magnetic polepiece parts and a back surface side of the yoke piece part of the firstiron core piece such that the first iron core piece is partially blankedfrom the sheet of workpiece material before simultaneously blanking afront end side of the magnetic pole piece parts and a back surface sideof the yoke piece part of the second iron core piece such that thesecond iron core piece is partially blanked from the sheet of workpiecematerial; and then blanking the plurality of iron core pieces, whichincludes the first iron core piece and the second iron core piece, suchthat the plurality of iron core pieces is completely separated from thesheet of workpiece material; after blanking, laminating two or more ofthe plurality of iron core pieces together to form the laminated ironcore.
 2. The method for manufacturing the laminated iron core accordingto claim 1, wherein each of the plurality of iron core pieces is anelongated iron core piece having the linear yoke piece part, and thelaminated iron core is formed by laminating the elongated iron corepieces and then annularly bending the elongated iron core pieces.
 3. Themethod for manufacturing the laminated iron core according to claim 1,wherein each of the plurality of iron core pieces is an elongated ironcore piece having the linear yoke piece part, and the laminated ironcore is formed by laminating while annularly winding the elongated ironcore pieces.
 4. The method for manufacturing the laminated iron coreaccording to claim 1, wherein each of the plurality of iron core piecesincludes a plurality of divided iron core pieces, and the laminated ironcore is formed by laminating and arranging the plurality of divided ironcore pieces annularly.
 5. The method for manufacturing the laminatediron core according to claim 1, wherein a part of the back surface sideof the yoke piece part of each of the plurality of iron core pieces isblanked such that a non-blanked portion remains, and the remainingnon-blanked portion of the back surface side of the yoke piece part issubsequently blanked when completely separating each of the plurality ofiron core pieces from the workpiece.
 6. The method for manufacturing thelaminated iron core according to claim 1, wherein the pair of iron corepieces are sequentially blanked in a state where a longitudinaldirection of each of the plurality of iron core pieces is aligned with adirection orthogonal to a conveyance direction of the sheet of workpiecematerial.
 7. The method for manufacturing the laminated iron coreaccording to claim 1, wherein the pair of iron core pieces aresequentially blanked in a state where a longitudinal direction of eachof the plurality of iron core pieces is aligned with a directiondifferent from a direction orthogonal to a conveyance direction of thesheet of workpiece material.
 8. The method for manufacturing thelaminated iron core according to claim 1, further comprising: blanking(i) a portion between lateral parts of the magnetic pole piece parts ofthe first iron core piece, which are adjacent each other and (ii)blanking a portion between lateral parts of the magnetic pole pieceparts of the second iron core piece, which are adjacent each other,before blanking the front end side of the magnetic pole piece parts andthe back surface side of the yoke piece part of each of the plurality ofiron core pieces.